The present disclosure relates generally to integrated circuit (IC) manufacturing, and more particularly to a method and an apparatus for measuring flicker noise (also referred to as 1/f noise) generated by defects present in an IC manufacturing environment.
The flicker noise is a type of electronic noise occurring mostly at low frequencies in virtually all electronic devices. Unlike thermal noise that has constant power amplitude over the frequency spectrum, the flicker noise decreases with frequency. The flicker noise is typically caused by material or process defects (or both) present in the IC manufacturing environment. The flicker noise is often used as a figure-of-merit (FOM) for comparing performances of semiconductor devices.
Ongoing scaling of semiconductor device dimensions, including the introduction of new channel materials and device structures, is having a significant impact on noise performance metrics. In particular, the flicker noise being intrinsically related to the interface properties is expected to be impacted by deep sub-micron technologies, especially in analog, mixed signal, and radio frequency (RF) circuits.
A traditional solution for measuring flicker noise properties of transistors in a production environment is typically based on fabrication of test circuits on a wafer and the use of highly sensitive, low noise amplifiers to measure the low frequency noise signals. The testing is typically performed in a more stringent measurement environment that is different than the production environment. However, since this technique relies on amplification and measurement of very low level analog signals, the measurement results are often erroneous, costly to obtain, and unreliable.